Distinct patterns of naive, activated and memory T and B cells in blood of patients with ulcerative colitis or Crohn's disease.

Both major subcategories of inflammatory bowel disease (IBD), ulcerative colitis and Crohn's disease are characterized by infiltration of the gut wall by inflammatory effector cells and elevated biomarkers of inflammation in blood and feces. We investigated the phenotypes of circulating lymphocytes in the two types of IBD in treatment-naive pediatric patients by analysis of blood samples by flow cytometry. Multivariate analysis was used to compare the phenotypes of the blood lymphocytes of children with ulcerative colitis (n = 17) or Crohn's disease (n = 8) and non-IBD control children with gastrointestinal symptoms, but no signs of gut inflammation (n = 23). The two IBD subcategories could be distinguished based on the results from the flow cytometry panel. Ulcerative colitis was characterized by activated T cells, primarily in the CD8+ population, as judged by increased expression of human leukocyte antigen D-related (HLA-DR) and the ß1-integrins [very late antigen (VLA)] and a reduced proportion of naive (CD62L+ ) T cells, compared with the non-IBD controls. This T cell activation correlated positively with fecal and blood biomarkers of inflammation. In contrast, the patients with Crohn's disease were characterized by a reduced proportion of B cells of the memory CD27+ phenotype compared to the non-IBD controls. Both the patients with ulcerative colitis and those with Crohn's disease showed increased percentages of CD23+ B cells, which we demonstrate here as being naive B cells. The results support the notion that the two major forms of IBD may partially have different pathogenic mechanisms.

Neonatal gut colonization by Staphylococcus aureus strains with certain adhesins and superantigens is negatively associated with subsequent development of atopic eczema.

BACKGROUND: Insufficient early immune stimulation may predispose to atopic disease. Staphylococcus aureus, a skin and gut colonizer, produces the B-cell mitogen protein A and T-cell-activating superantigens. Early gut colonization by S. aureus strains that possess the superantigens encoded by the enterotoxin gene (egc) cluster and elastin-binding protein is negatively associated with development of atopic eczema. OBJECTIVES: To investigate (i) whether these findings could be replicated in a second birth cohort, FARMFLORA, and (ii) whether nasal colonization by S. aureus also relates to subsequent atopic eczema development. METHODS: Faecal samples and nasal swabs from infants in the FARMFLORA birth cohort (n = 65) were cultured for S. aureus. Individual strains were distinguished by random amplified polymorphic DNA and assessed for adhesin and superantigen gene carriage by polymerase chain reaction. Atopic eczema at 18 months of age was related to nasal and gut S. aureus colonization patterns during the first 2 months of life (well before onset of eczema). RESULTS: Staphylococcus aureus colonization per se was unrelated to subsequent eczema development. However, gut S. aureus strains from the infants who subsequently developed atopic eczema less frequently carried the ebp gene, encoding elastin-binding protein, and superantigen genes encoded by egc, compared with strains from children who remained healthy. Nasal colonization by S. aureus was less clearly related to subsequent eczema development. CONCLUSIONS: The results precisely replicate our previous observations and may suggest that mucosal colonization by certain S. aureus strains provides immune stimulation that strengthens the epithelial barrier and counteracts the development of atopic eczema.

Tissue-specific Differences in Immune Cell Subsets Located in the Naso-oropharyngeal-associated Lymphoid Tissues.

Defining the immune cells within the naso-oropharyngeal-associated lymphoid tissues would promote the development of efficient orally and nasally delivered immunotherapies. The aim was to compare murine antigen-presenting cells (APCs) and T cell subsets in the nose-associated lymphoid tissues (NALT), cervical lymph nodes (CLN), mesenteric lymph nodes (MLN) and peripheral lymph nodes (PLN) using flow cytometry and in vitro proliferation assays. Overall, the NALT contained a higher proportion of APCs and a lower proportion of T cells compared to the CLN, MLN and PLN. The APCs of the NALT more often belonged to the CD11c+ CD11b+ and the CD11cneg CD11b+ subsets as compared to the other sites. Both of these APC populations showed little sign of activation, that is low expression of the markers CD40, CD86 and IAd. Instead, the APCs of the NALT more often co-expressed CX3CR1 and CD206, markers associated with a tolerogenic function. No increase in the proportion of regulatory T cells was observed in the NALT. Instead, the T cells frequently exhibited a memory/effector phenotype, expressing the homing markers α4ß7, CCR4 and CCR9, but rarely the naïve phenotype cell surface marker CD45RB. In contrast, the T cells at the other sites were mostly of the naïve phenotype. In addition, cells from the NALT did not proliferate upon in vitro stimulation with Con A, whereas the cells from the other sites did. Taken together, these results suggest that the NALT is primarily an effector site rather than one for activation and differentiation, despite it being regarded as a site of induction.

Late introduction of fish and eggs is associated with increased risk of allergy development - results from the FARMFLORA birth cohort.

The prevalence of allergy is markedly low in children growing up on farms. An increasing number of studies indicate that the timing of food introduction may affect allergy development. We aimed to investigate if protection against allergy in farm environments may be mediated through differences in food-introduction practices between farm and non-farm families, using an explorative approach. Twenty-eight farm and 37 non-farm children were included in the FARMFLORA birth cohort. Practices of breastfeeding and introduction of formulas and complementary foods were collected by questionnaires at 6, 12, and 18 months of age. Allergy was diagnosed by pediatricians at 3 years of age. The only difference in food-introduction practices observed between farm and non-farm children was an earlier introduction of nuts in farmers (median month: 11 [IQR: 8-6] in farmers, 15 [12-19] in non-farmers). One farm child (4%) and 10 non-farm children (27%) were allergic at 3 years of age. Lower risk of allergy development was associated with early exclusive breastfeeding (continuous variable; OR = 0.59, 95% CI: 0.39-0.89), but also having received eggs (OR = 0.08, 95% CI: 0.13-0.54) and fish (logistic regression not applicable, P = 0.01 in likelihood ratio testing [χ2]) at 10 months of age or earlier compared to later. Our results were not affected by reverse causation, as judged by a questionnaire sent to the families in retrospect. Timing of introduction of complementary foods is unlikely to contribute to the lower risk of allergy among farm children. Although early exclusive breastfeeding was associated with a lower rate of allergy development, postponed introduction of complementary foods might increase the risk of developing allergy. Owing to the limited sample size, our results are only indicative, but support prior findings.

Allergic disease in 8-year-old children is preceded by delayed B cell maturation.

BACKGROUND: We previously reported that exposure to a farming environment is allergy-protective, while high proportions of neonatal immature/naïve CD5+ B cells and putative regulatory T cells (Tregs) are risk factors for development of allergic disease and sensitization up to 3 years of age. OBJECTIVE: To examine if B and T cell maturation are associated with allergic disease and farming environment over the first 8 years in life. METHODS: In the prospective FARMFLORA study, including both farming and non-farming families, 48 of 65 children took part in the 8-year follow-up study. Various B and T cell maturation variables were examined in blood samples obtained at several occasions from birth to 8 years of age and related to doctors' diagnosed allergic disease and sensitization, and to farming environment. RESULTS: We found that the incidence of allergic disease was lower among farmers' compared to non-farmers' children during the 8-year follow-up period, and that farmers' children had higher proportions of memory B cells at 8 years of age. Moreover, a high proportion of neonatal CD5+ B cells was a risk factor for and may predict development of allergic disease at 8 years of age. A high proportion of Tregs was not protective against development of these conditions. CONCLUSION AND CLINICAL RELEVANCE: High proportions of neonatal naïve B cells remained as a risk factor for allergic disease in school-aged children. Thus, the accelerated B cell maturation observed among farmers' children may be crucial for the allergy-protective effect of a farming environment.

Life after stroke in Appalachia.

OBJECTIVE: The purpose of this study was to describe the structure of meaning in the experience of surviving stroke for adults living in Appalachia. METHODS: This qualitative phenomenological study includes a sample of 6 adult survivors of ischemic stroke who were discharged from either a community or university hospital to home in the Appalachian region. Data was collected through semi-structured interviews, transcribed, and analyzed thematically by two investigators. The explicated themes were verified by the survivors as representative of their experience. RESULTS: Five main themes emerged: 1) Frustration with new physical and functional impairment, 2) Negative emotions including anger, guilt, loneliness, and depression 3) Need for accessible support, 4) Longing for home during recovery and, 5) Stepping forward after stroke which included sub-themes of perseverance, acceptance, and retraining. Anger was described as contributing to delayed recover and emotional lability was described as a source of anger. The familiarity of home was viewed as key to reestablishing control over one's life. Survivors described how they developed perseverance to move forward and emphasized that willingness to participate in retraining led to adapting to impairments. Acceptance was described as letting go of prior expectations of self and others so one could live in the present.

Antibiotic resistance is linked to carriage of papC and iutA virulence genes and phylogenetic group D background in commensal and uropathogenic Escherichia coli from infants and young children.

P fimbriae, enabling adherence to colonic and urinary epithelium, and aerobactin, an iron sequestering system, are both colonization factors in the human colon and virulence factors for urinary tract infection. The colonic microbiota is suggested to be a site suitable for the transfer of antibiotic resistance genes. We investigated whether phenotypic resistance to antibiotics in commensal and uropathogenic Escherichia coli from infants and young children is associated with carriage of virulence genes and to phylogenetic group origin and, in the case of fecal strains, to persistence in the gut and fecal population levels. The commensal strains (n = 272) were derived from a birth cohort study, while the urinary isolates (n = 205) were derived from outpatient clinics. Each strain was assessed for phenotypic antibiotic resistance and for carriage of virulence genes (fimA, papC, sfaD/E, hlyA, iutA, kfiC, and neuB), phylogenetic group (A, B1, B2, or D), and markers of particular virulent clones (CGA-D-ST69, O15:H1-D-ST393, and O25b:H4-B2-ST131). Resistance to ampicillin, tetracycline, and trimethoprim was most prevalent. Multivariate analysis showed that resistance to any antibiotic was significantly associated with carriage of genes encoding P fimbriae (papC) and aerobactin (iutA), and a phylogenetic group D origin. Neither fecal population numbers nor the capacity for long-term persistence in the gut were related to antibiotic resistance among fecal strains. Our study confirms the importance of phylogenetic group D origin for antibiotic resistance in E. coli and identifies the virulence genes papC and iutA as determinants of antibiotic resistance. The reason for the latter association is currently unclear.

Superantigens and adhesins of infant gut commensal Staphylococcus aureus strains and association with subsequent development of atopic eczema.

BACKGROUND: According to the hygiene hypothesis, insufficient immune activation by microbes increases the risk of allergy development. Staphylococcus aureus, which is part of the skin and gut microbiota of infants in Western countries, produces a variety of T-cell-activating enterotoxins, called superantigens. OBJECTIVES: To investigate whether early (0-2 months of age) gut colonization by S. aureus strains that carry specific superantigens and adhesins was related to subsequent development of atopic eczema in a Swedish birth cohort. METHODS: Staphylococcus aureus was isolated from rectal swabs and cultured quantitatively from faecal samples, with individual strains being tested for carriage of genes for superantigens and adhesins. Atopic eczema was diagnosed at onset of symptoms and at 18 months of age. RESULTS: Although the frequency of early gut colonization by S. aureus was not related to subsequent eczema development, the S. aureus strains that were found to colonize those infants who developed atopic eczema were less likely to carry the gene encoding the superantigen SElM (P = 0·008) and the gene for elastin-binding protein (P = 0·03), compared with strains that were isolated from infants who had not developed atopic eczema by 18 months of age. CONCLUSIONS: Gut colonization by S. aureus strains carrying a certain combination of superantigen and adhesin genes was negatively associated with subsequent development of atopic eczema. Such strains may provide stimulation and promote maturation of the infant immune system.

5-HTTLPR/rs25531 polymorphism and neuroticism are linked by resting state functional connectivity of amygdala and fusiform gyrus.

The s/s-genotype of the 5-HTTLPR polymorphism and the personality trait of neuroticism have both been associated with experiences of negative affect, anxiety and mood disorders, as well as an emotional processing bias towards negative facial emotions. On a neural level, this bias can be characterized by altered amygdala and fusiform gyrus (FFG) activity during perception of negative facial expressions. Using resting-state functional magnetic resonance imaging in a multi-center-sample of 178 healthy subjects of European descent, this study investigated the association of 5-HTTLPR (short s- and long l-allele) including the genotype of the single nucleotide polymorphism (SNP) rs25531 (A/G) within this region polymorphism, and trait neuroticism on resting-state functional connectivity (rs-FC) between amygdala and the FFG. Moreover, we aimed to identify additional brain regions with associations of 5-HTTLPR/rs25531 (combined according to its expression; low: s/s; high: l(A)/l(A); intermediate: s/l(A), s/l(G), l(G)/l(G), l(A)/l(G)) and trait neuroticism to amygdala rs-FC. Separate analyses for 5-HTTLPR/rs25531 and neuroticism (controlling for age, gender, handedness, and research site) revealed that s/s-homozygotes and individuals high in neuroticism obtained altered amygdala rs-FC in the right occipital face area, which is considered to be a "core component" of the face processing system. Importantly, effects of neuroticism were replicated across three independent research sites. Additionally, associations of 5-HTTLPR/rs25531 genotype and amygdala rs-FC were observed in the anterior and posterior cingulate cortex, whereas neuroticism was not related to rs-FC in these areas. The presented data implies that 5-HTTLPR/rs25531 variants and neuroticism are linked by resting state functional connectivity of amygdala and fusiform gyrus and suggests that variants of 5-HTTLPR/rs25531 genotype and different levels of neuroticism may partly account for altered processing of negative facial emotions.

High Thrill and adventure seeking is associated with reduced interoceptive sensitivity: evidence for an altered sex-specific homeostatic processing in high sensation seekers.

OBJECTIVE: The personality trait of sensation seeking (SS) has been traditionally linked to the construct of exteroception, i.e. sensing of the outside world. Little is known about the relationship between SS and interoception, i.e. sensing originating in the body. Interoceptive sensations have strong affective and motivational components that may influence behaviors such as risk-taking in SS. This investigation examined whether interoceptive differences contribute to different behavioral characteristics in SS. METHOD: Using an inspiratory resistive load breathing task, the response to an aversive interoceptive stimulus as a basic homeostatic process was studied in 112 subjects (n=74 females, 38 males). A linear-mixed model approach was used to examine the influence of thrill and adventure seeking (TAS) on the interoceptive response across three levels of breathing resistances (10, 20, 40 cmH2O/L/sec). RESULTS: High relative to low TAS individuals were less responsive in evaluating intensities of perceived choking with increasing inspiratory resistive loads. This effect was driven by male, but not female high TAS individuals and was particularly associated with reduced interoceptive sensitivity in males. CONCLUSION: The conceptualization of SS as primarily driven by exteroceptive stimuli can be expanded to a view of an altered homeostasis in SS, specifically in males.

High proportions of FOXP3(+) CD25(high) T cells in neonates are positively associated with allergic sensitization later in childhood.

BACKGROUND: The role of FOXP3(+) regulatory T cells in the prevention against sensitization and allergy development is controversial. OBJECTIVE: We followed 65 newborn Swedish children from farming and non-farming families from birth to 3 years of age and investigated the relation between CD4(+) T cell subsets in blood samples and development of sensitization and allergic disease. METHODS: The proportions of FOXP3(+) CD25(high) , CTLA-4(+) CD25(+) , CD45RO(+) , HLA-DR(+) , CCR4(+) or α4ß7(+) within the CD4(+) T cell population were examined by flow cytometry of blood samples at several time-points. Mononuclear cells were isolated from blood and stimulated with birch allergen, ovalbumin or the mitogen PHA, and the levels of IL-1ß, IL-6, TNF, IFN-γ, IL-5 and IL-13 were measured. A clinical evaluation regarding the presence of allergen-specific IgE and allergy was performed at 18 and 36 months of age. RESULTS: Multivariate discriminant analysis revealed that children who were sensitized at 18 or 36 months of age had higher proportions of FOXP3(+) CD25(high) T cells at birth and at 3 days of life than children who remained non-sensitized, whereas allergy was unrelated to the neonatal proportions of these cells. The proportions of CTLA-4(+) CD25(+) T cells were unrelated to both sensitization and allergy. The association between higher proportions of FOXP3(+) CD25(high) T cells and sensitization persisted after exclusion of farmer's children. Finally, a farming environment was associated with lower proportions of FOXP3(+) CD25(high) T cells in early infancy and to a more prominent T cell memory conversion and cytokine production. CONCLUSION & CLINICAL RELEVANCE: Our results indicate that high proportions of FOXP3(+) CD25(high) T cells in neonates are not protective against later sensitization or development of allergy.

Metabolic Syndrome and its Profound Effect on Prevalence of Ischemic Stroke.

Ischemic stroke represents a leading cause of death worldwide and the leading cause of disability in the United States. Greater than 8% of all deaths are attributed to ischemic stroke. This rate is consistent with the heightened burden of cardiovascular disease deaths. Treatments for acute ischemic stroke remain limited to tissue plasminogen activator and mechanical thrombolysis, both of which require significant medical expertise and can only be applied to a select number of patients based on time of presentation, imaging, and absence of contraindications. Over 1,000 compounds that were successful in treating ischemic stroke in animal models have failed to correlate to success in clinical trials. The search for alternative treatments is ongoing, drawing greater attention to the importance of preclinical models that more accurately represent the clinical population through incorporation of common risk factors. This work reviews the contribution of these commonly observed risk factors in the clinical population highlighting both the pathophysiology as well as current clinical diagnosis and treatment standards. We also highlight future potential therapeutic targets, areas requiring further investigation, and recent changes in best-practice clinical care.

Differential effect on cell-mediated immunity in human volunteers after intake of different lactobacilli.

Probiotics are live microorganisms which have beneficial effects on the host when ingested in adequate amounts. Probiotic bacteria may stimulate immune effector functions in a strain-specific manner. In this blind placebo-controlled trial, we investigated the effects on the immune system following daily intake of six different strains of lactobacilli or the Gram-negative bacterium Pseudomonas lundensis for 2 or 5 weeks. Blood lymphocyte subsets were quantified by fluorescence activated cell sorter and the expression of activation and memory markers was determined. The bacterial strains were also examined for their capacity to adhere to human intestinal cells and to be phagocytosed by human peripheral blood mononuclear cells. Intake of Lactobacillus plantarum strain 299v increased the expression of the activation marker CD25 (P = 0·01) on CD8(+) T cells and the memory cell marker CD45RO on CD4(+) T cells (P = 0·03), whereas intake of L. paracasei tended to expand the natural killer T (NK T) cell population (P = 0·06). The phagocytic activity of granulocytes was increased following intake of L. plantarum 299v, L. plantarum HEAL, L. paracasei or L. fermentum. In contrast, ingestion of L. rhamnosus decreased the expression of CD25 and CD45RO significantly within the CD4(+) cell population. The observed immune effects after in-vivo administration of the probiotic bacteria could not be predicted by either their adherence capacity or the in-vitro-induced cytokine production. The stimulation of CD8(+) T cells and NK T cells suggests that intake of probiotic bacteria may enhance the immune defence against, e.g. viral infections or tumours.

Age and the metabolic syndrome as risk factors for ischemic stroke: improving preclinical models of ischemic stroke.

Ischemic stroke represents a leading cause of morbidity and mortality in the developed world. This disabling and sometimes fatal event puts an ever increasing burden on the family members and medical professionals who care for stroke victims. Preclinical ischemic stroke research has predominantly utilized young adult, healthy animals, a clear discrepancy when considering the clinical population affected by stroke. A broad spectrum of risk factors such as age, obesity, diabetes, and hypertension has been associated with an increased stroke risk. The effect of these comorbidities on both stroke pathophysiology and outcome has not been emphasized and has been recognized as a shortcoming of preclinical studies. By addressing these conditions in experimental models of ischemic stroke, it may be possible to more accurately represent the clinical scenario and improve therapeutic translation from bench-to-bedside. In this work, we review many of the risk factors associated with increased stroke risk, particularly as each risk factor relates to inflammation. Additionally, we explore potential animal models that could be utilized in identifying the contribution of these risk factors to stroke outcome. By investigating the risk factors for stroke and how these may alter stroke pathophysiology, the present discrepancies between preclinical studies and the clinical reality can be reconciled in an effort to improve therapeutic development and translation from bench-to-bedside.

Ready-to-Eat Cereal Consumption Patterns: The Relationship to Nutrient Intake, Whole Grain Intake, and Body Mass Index in an Older American Population.

Objective. To investigate the relationship between ready-to-eat (RTE) breakfast cereal consumption patterns and body mass index (BMI), nutrient intake, and whole grain intake in an older American population. Design. A cross-sectional survey of US households, collected by the NPD Group via the National Eating Trends (NET) survey. Main outcome measures include BMI, nutrient intake, and whole grain intake. Subjects/Setting. The sample included 1759 participants age 55 and older, which was divided into approximate quartiles based on intake of RTE breakfast cereal for the 2-week period (0 servings, 1-3 servings, 4-7 servings, and ≥8 servings). Results. In the multivariate linear regression analysis adjusted for energy and age; intake of dietary fiber, whole grains, and the majority of micronutrients examined were found to be positively associated with frequent RTE cereal consumption. The proportion of participants consuming less than the Estimated Average Requirement (EAR) was lower for the highest quartile of RTE cereal consumers compared to nonconsumers, for the majority of vitamins and minerals examined. Significant differences in BMI between RTE breakfast cereal intake groups were found for men. Conclusion. Results suggest that ready-to-eat breakfast cereals may contribute to the nutritional quality of the diets of older Americans. Prospective studies and experimental trials are needed to better evaluate the role of RTE cereal consumption in energy balance.

Retention of ice-associated amphipods: possible consequences for an ice-free Arctic Ocean.

Recent studies predict that the Arctic Ocean will have ice-free summers within the next 30 years. This poses a significant challenge for the marine organisms associated with the Arctic sea ice, such as marine mammals and, not least, the ice-associated crustaceans generally considered to spend their entire life on the underside of the Arctic sea ice. Based upon unique samples collected within the Arctic Ocean during the polar night, we provide a new conceptual understanding of an intimate connection between these under-ice crustaceans and the deep Arctic Ocean currents. We suggest that downwards vertical migrations, followed by polewards transport in deep ocean currents, are an adaptive trait of ice fauna that both increases survival during ice-free periods of the year and enables re-colonization of sea ice when they ascend within the Arctic Ocean. From an evolutionary perspective, this may have been an adaptation allowing success in a seasonally ice-covered Arctic. Our findings may ultimately change the perception of ice fauna as a biota imminently threatened by the predicted disappearance of perennial sea ice.

Low breast milk levels of long-chain n-3 fatty acids in allergic women, despite frequent fish intake.

BACKGROUND: Long-chain n-3 polyunsaturated fatty acids (PUFAs) have immune regulating and anti-inflammatory effects. However, their role in allergic disease is unclear. Allergic diseases are immunologically heterogeneous, and we hypothesized that n-3 fatty acid composition in serum and breast milk may vary according to clinical manifestations. Further, animal studies have shown reduction of serum-PUFA levels during allergic inflammation. OBJECTIVE: To investigate fatty acid composition in breast milk and serum from women with different atopic disease manifestations. Secondly, to determine whether low PUFA levels reflected insufficient intakes. METHODS: Fatty acids were analysed in breast milk and serum of women with atopic eczema and respiratory allergy (n=16), only respiratory allergy (n=7), as well as healthy women (n=22). Dietary intake of foods expected to affect long-chain n-3 PUFA levels were estimated by food-frequency questionnaire. The fatty acid pattern was related to diagnostic group and intake of relevant food items using a multivariate pattern recognition method (partial least squares projections to latent structures and discriminant analysis). Results Women with a combination of eczema and respiratory allergy had lower breast milk levels of several PUFAs (arachidonic acid, eicosapentaenoic acid, EPA, docosahexaenoic acid, DHA, and docosapentaenoic acid, DPA), and a lower ratio of long-chain n-3 PUFAs/n-6 PUFAs. Their PUFA levels differed not only from that of healthy women, but also from that of women with only respiratory allergy. The latter had a fatty acid pattern similar to that of healthy women. Despite low EPA, DHA and DPA levels women with eczema and respiratory allergy consumed no less fish than did healthy women. CONCLUSION & CLINICAL RELEVANCE: Our data suggest that reduced levels of long-chain n-3 fatty acids in serum and breast milk characterize women with extensive allergic disease including eczema, and are not related to low fish intake. Consumption of PUFAs during the allergic process may explain these findings.

Effect of lifestyle factors on Staphylococcus aureus gut colonization in Swedish and Italian infants.

In recent years, Staphylococcus aureus has become a common bowel colonizer in Swedish infants. We aimed to identify host factors that determine such colonization. Stool samples from 100 Italian and 100 Swedish infants were obtained on seven occasions during the first year of life and cultured quantitatively for S. aureus. In a subgroup of infants in each cohort, individual strains were identified by random amplified polymorphic DNA analysis. Colonization at each time-point was related to delivery mode, siblings in family and antibiotic treatment. In total, 66% of the Italian and 78% of the Swedish infants had S. aureus in their stools on at least one time-point (p 0.08) and 4% of Italian and 27% of Swedish infants were positive on at least six of the seven time-points investigated (p 0.0001). Most infants analysed regarding strain carriage harboured a single strain in their microbiota for several months. The S. aureus stool populations in colonized infants decreased from 10(7) to 10(4) colony-forming units/g between 1 week and 1 year of age in both cohorts. In multivariate analysis, the strongest predictor for S. aureus colonization was being born in Sweden (OR 3.4 at 1 week of age, p 0.002). Having (an) elder sibling(s) increased colonization at peak phase (OR 1.8 at 6 months, p 0.047). Antibiotic treatment was more prevalent among Italian infants and correlated negatively with S. aureus colonization at 6 months of age (OR 0.3, p 0.01). To conclude, S. aureus is a more common gut colonizer in Swedish than Italian infants, a fact that could not be attributed to feeding or delivery mode.

Infection of infants with human herpesvirus type 6 may be associated with reduced allergic sensitization and T-helper type 2 development.

BACKGROUND: Epidemiological studies point to an inverse relationship between microbial exposure and the prevalence of allergic diseases. The underlying mechanism for this observation remains largely unknown, as well as the nature of the microbes involved. OBJECTIVE: To investigate the effects of early infection with human herpesviruses (HHVs) on IgE formation and T-helper type 2 (Th2) development in infants. METHODS: Serum was collected from children aged 18 months and assessed for IgE to common allergens and IgG to five common herpesviruses. Cord blood plasmacytoid dendritic cells (pDC) were exposed to HHV type 6 in vitro and mixed with allogeneic cord blood CD4(+) T cells. Cytokine levels were determined by ELISA and by flow cytometry. RESULTS: We found that children seropositive at 18 months of age to HHV type 6 were significantly less often IgE sensitized than seronegative children [odds ratio (OR): 0.08, 95% confidence interval (CI): 0.009-0.68]. HHV type 6 also decreased the production of the Th2-associated cytokines IL-5 and IL-13 by CD4(+) T cells when co-cultured with allogeneic cord blood pDC. This was associated with an increased production of IFN-alpha by pDC exposed to HHV type 6. CONCLUSION: These data indicate that an early childhood infection with HHV type 6 could down-regulate Th2 responses and reduce IgE formation to common allergens in a young child.

Long-chain polyunsaturated fatty acids are consumed during allergic inflammation and affect T helper type 1 (Th1)- and Th2-mediated hypersensitivity differently.

Studies have shown that atopic individuals have decreased serum levels of n-3 fatty acids. Indicating these compounds may have a protective effect against allergic reaction and/or are consumed during inflammation. This study investigated whether fish (n-3) or sunflower (n-6) oil supplementation affected T helper type 1 (Th1)- and Th2-mediated hypersensitivity in the skin and airways, respectively, and whether the fatty acid serum profile changed during the inflammatory response. Mice were fed regular chow, chow + 10% fish oil or chow + 10% sunflower oil. Mice were immunized with ovalbumin (OVA) resolved in Th1 or Th2 adjuvant. For Th1 hypersensitivity, mice were challenged with OVA in the footpad. Footpad swelling, OVA-induced lymphocyte proliferation and cytokine production in the draining lymph node were evaluated. In the airway hypersensitivity model (Th2), mice were challenged intranasally with OVA and the resulting serum immunoglobulin (Ig)E and eosinophilic lung infiltration were measured. In the Th1 model, OVA-specific T cells proliferated less and produced less interferon (IFN)-gamma, tumour necrosis factor (TNF) and interleukin (IL)-6 in fish oil-fed mice versus controls. Footpad swelling was reduced marginally. In contrast, mice fed fish oil in the Th2 model produced more OVA-specific IgE and had slightly higher proportions of eosinophils in lung infiltrate. A significant fall in serum levels of long-chain n-3 fatty acids accompanied challenge and Th2-mediated inflammation in Th2 model. Fish oil supplementation affects Th1 and Th2 immune responses conversely; significant consumption of n-3 fatty acids occurs during Th2-driven inflammation. The latter observation may explain the association between Th2-mediated inflammation and low serum levels of n-3 fatty acids.